scholarly journals Removal of Calcium Carbonate Water-Based Filter Cake Using a Green Biodegradable Acid

2020 ◽  
Vol 12 (3) ◽  
pp. 994 ◽  
Author(s):  
Abdelmjeed Mohamed ◽  
Salaheldin Elkatatny ◽  
Abdulaziz Al-Majed

The filter cake is a very thin layer of solid particles deposited from the drilling fluid onto the surface of the drilled formation. This is essential during the drilling process as it reduces fluid filtrate invasion, contributing for the well’s integrity. When the drilling processes are over, this formation must be removed efficiently to allow for the primary cement jobs to be conducted efficiently, and for hydrocarbons to be produced without any restrictions. The removal process of the filter cake is challenging and requires specific techniques, depending on several factors including the filter cake homogeneity, drilling fluid components, weight of materials used, and the continuous phase of the drilling fluid (i.e., water or oil). This study evaluates the use of green biodegradable removal acid (GBRA) to dissolve calcium carbonate water-based filter cake. The removal efficiency of this new acid was analyzed using filtration and removal tests, conducted on a ceramic filter disc and real core samples at 212 °F. Then, the new formulation was subjected to physical properties measurements and biodegradation and corrosion tests. Furthermore, the performance of the new acid formulation was compared with 10 wt.% hydrochloric acid (HCl) to ensure its efficiency. The obtained results showed that the new acid formulation was effective at removing the filter cake, with a removal efficiency greater than 90%. The retained permeability was 100% and 94% with the ceramic filter disc and the real limestone core sample, respectively, confirming the good removal performance of the new acid formulation. The corrosion rate of GBRA (50 wt.%) at 212 °F was 0.032 lb/ft2, which was within the acceptable range according to oil industry practices (i.e., less than 0.05 lb/ft2 if the temperature is less than 250 °F), while HCl (10 wt.%) yielded a high corrosion rate of 0.68 lb/ft2.

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Badr S. Ba geri ◽  
Mohamed Mahmoud ◽  
Saleh. H. Al-Mutairi ◽  
Abdulazeez Abdulraheem

The drilling mud program contains many tests such as filtration rate and filter cake properties to select the proper drilling fluid additives that yield the standard ranges of the viscosity, filtration rate, etc. However, the physical and chemical changes in the mud composition during the mud circulating will cause changes to the filter cake properties. The changes in the filter cake properties should be considered in the mud design program to prevent the problems associated with the change in the drilling fluid properties. For long horizontal wellbores penetrating plastic formations, the two sources of solids in filter cake are drilling chemical additives and formation cuttings (sand particles in the case of sandstone reservoir). This study focuses on the effect of introducing sand particles from the drilled—formations on the filter cake properties. Real drilling fluid samples from the field were collected at different location during drilling a 3600 ft of the horizontal section of a sandstone formation. Calcium Carbonate (CaCO3) was used as weighting material in this filed. The drilling fluid samples were collected at two different points: the flow line coming from the well after shale shaker and the flow line going to the well to verify the effect of separation stages on filter cake properties. The primary drilling fluid properties of the collected samples were measured such as density and rheological parameters. High pressure high temperature (HPHT) filter press was used to perform the filtration and filter cake experiments at 300 psi differential pressure and room temperature (25 °C). The mineralogy of the external filter cake formed by fluid loss cell is determined using SEM (scanning electron microscopy) and XRD (X-ray diffraction). Finally, solubility test was conducted to evaluate the effect of sand particles on filter cake removal (containing Calcium Carbonate as weighting material) using chelating agent: glutamic diacetic acid (GLDA) at pH 4. The results showed that for long horizontal sections, the effect of introducing sand particles to the composition of the filter cake can cause significant change to the properties of filter cake such as mineralogy, thickness, porosity, and permeability. For instant the thickness of filter cake increased about 40% of its original thickness when drilling sandstone formation in horizontal well due to fine sand particle settling. The filter cake porosity and permeability increment in the first 2000 ft part of the horizontal section was observed clearly due to the irregular shape of the drilling particles. However for the points after the first 2000 ft of horizontal lateral, the porosity and permeability almost remained constant. Increasing the sand content up to 20% degrade the dissolution rate of calcium carbonate in the GLDA (pH = 3.8) to 80% instead of 100%.


2014 ◽  
Vol 262 ◽  
pp. 51-61 ◽  
Author(s):  
Rugang Yao ◽  
Guancheng Jiang ◽  
Wei Li ◽  
Tianqing Deng ◽  
Hongxia Zhang

2019 ◽  
Vol 8 (4) ◽  
pp. 9720-9722

Drilling fluid or mud is essential fluid in drilling operation which has many important properties and one of the important properties is the viscosity of the drilling fluid and the viscosity is further classified as yield viscosity and plastic viscosity which means different in terms of its function. This paper is attempting to show the rheological characteristics of the different samples of the drilling fluid using Xanthan Gum and Physillum husk and different weighting agents Barite and Calcium Carbonate at ambient conditions. The results showed that xanthan gum acts as good viscosifying agent as compared with physillum husk. In addition that, the water based drilling mud with barite which act as weighing agent proved better as compared with calcium carbonate. The following paper will be valuable to the graduates, future graduates and also to the Industry personnel have a basic idea about the rheology and how the parameters related to the rheology are valuable in mud design.


2021 ◽  
Vol 5 (2) ◽  
pp. 1-14
Author(s):  
Mahmoud O

The increasing demand for deeper drilling and more complicated wells fastens the way for improved drilling fluid (mud) technologies and promising additives. Several studies have shown numerous improvements in mud characteristics upon using ilmenite compared to the commonly used weighting materials. This study aims at investigating the removal of filter cake deposited by ilmenite water-based drilling fluid under harsh conditions using low-concentration (7.5 wt%) of hydrochloric acid (HCl) and chelating agent (HEDTA) to prevent iron precipitation during reaction. API filter press was used to conduct the filtration tests and generate the filter cake at a pressure ~ 300 psi and temperature ~ 250°F. Different sandstone cores of 2.5-in. diameter and 1-in. thickness were used to simulate the formation during filtration. Filtrate fluids were collected for 30 minutes as per API procedures and computerized tomography (CT) scan was used to characterize the cores with the deposited filter cakes. The filter cakes were soaked with HCl–chelate solution for six hours. Cores with the remaining filter cakes were CT scanned again. Effluent solutions resulting from the aforementioned soaking process were analyzed using inductively coupled plasma (ICP). Scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS) was used to analyze the dried filter cakes and remaining residue. CT scan and SEM-EDS showed two layers of the filter cake with different densities but similar elemental composition. Using 7.5 wt% of HCl can partially remove the filter cake generated by ilmenite water-based drilling fluids. Adding the chelate showed minimal impact on the filter cake removal-efficiency; however, it helped nullify the corrosion issues during the treatment. This study provides a step forward on the way to chemically remove ilmenite-based filter cake using low acid concentration and virtually overcome corrosion issues encountered while acidizing.


2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Jimoh K. Adewole ◽  
Musa O. Najimu

This study investigates the effect of using date seed-based additive on the performance of water-based drilling fluids (WBDFs). Specifically, the effects of date pit (DP) fat content, particle size, and DP loading on the drilling fluids density, rheological properties, filtration properties, and thermal stability were investigated. The results showed that dispersion of particles less than 75 μm DP into the WBDFs enhanced the rheological as well as fluid loss control properties. Optimum fluid loss and filter cake thickness can be achieved by addition of 15–20 wt % DP loading to drilling fluid formulation.


Author(s):  
Petar Mijić ◽  
Nediljka Gaurina-Međimurec ◽  
Borivoje Pašić

About 75% of all formations drilled worldwide are shale formations and 90% of all wellbore instability problems occur in shale formations. This increases the overall cost of drilling. Therefore, drilling through shale formations, which have nanosized pores with nanodarcy permeability still need better solutions since the additives used in the conventional drilling fluids are too large to plug them. One of the solutions to drilling problems can be adjusting drilling fluid properties by adding nanoparticles. Drilling mud with nanoparticles can physically plug nanosized pores in shale formations and thus reduce the shale permeability, which results in reducing the pressure transmission and improving wellbore stability. Furthermore, the drilling fluid with nanoparticles, creates a very thin, low permeability filter cake resulting in the reduction of the filtrate penetration into the shale. This thin filter cake implies high potential for reducing the differential pressure sticking. In addition, borehole problems such as too high drag and torque can be reduced by adding nanoparticles to drilling fluids. This paper presents the results of laboratory examination of the influence of commercially available nanoparticles of SiO2 (dry SiO2 and water-based dispersion of 30 wt% of silica), and TiO2 (water-based dispersion of 40 wt% of titania) in concentrations of 0.5 wt% and 1 wt% on the properties of water-based fluids. Special emphasis is put on the determination of lubricating properties of the water-based drilling fluids. Nanoparticles added to the base mud without any lubricant do not improve its lubricity performance, regardless of their concentrations and type. However, by adding 0.5 wt% SiO2-disp to the base mud with lubricant, its lubricity coefficient is reduced by 4.6%, and by adding 1 wt% TiO2-disp to the base mud with lubricant, its lubricity coefficient is reduced by 14.3%.


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